Benchmark: Array.reduce2 - MeasureThat.net

Tests:

Using the spread operator
const users = [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }] users.reduce((x, user) => ({...x, [user.id]: user}), {});
Using Object.assign
const users = [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }] users.reduce((x, user) => Object.assign(x, { [user.id]: user }), {});
Returning the reference
const users = [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }] users.reduce((x, user) => { x[user.id] = user; return x; }, {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign
Returning the reference

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and analyze what's being tested.

**Benchmark Definition**

The benchmark definition is a simple JavaScript function that performs an array reduction on an object. The purpose of this function is to take an array of objects, where each object has an `id` property and a `name` property, and merge them into a single object. The function uses the `reduce()` method to iterate over the array and create the new object.

**Options being compared**

There are three different approaches being tested:

1. **Using the spread operator**: This approach uses the `Object.assign()` method with the spread operator (`...`) to merge the objects.
2. **Using Object.assign()**: This approach uses the `Object.assign()` method without the spread operator to merge the objects.
3. **Returning the reference**: This approach returns a new object from the reducer function, which allows the original object to be modified.

**Pros and Cons of each approach**

1. **Using the spread operator**
	* Pros:
		+ More concise and expressive code
		+ Allows for easy handling of nested objects
	* Cons:
		+ May not work as expected in older browsers that don't support the spread operator
2. **Using Object.assign()**
	* Pros:
		+ Works in older browsers that don't support the spread operator
		+ Easy to understand and implement
	* Cons:
		+ Can lead to unnecessary cloning of objects, which can impact performance
3. **Returning the reference**
	* Pros:
		+ Allows for easy modification of the original object
		+ May be more efficient than using `Object.assign()`
	* Cons:
		+ Requires careful consideration of how the reducer function interacts with the original object

**Library usage**

There is no explicit library usage in these benchmark definitions. However, it's worth noting that the `reduce()` method and `Object.assign()` are built-in JavaScript methods.

**Special JS features or syntax**

The only special feature being tested is the spread operator (`...`), which was introduced in ECMAScript 2015 (ES6). The other two approaches use older methods (`Object.assign()`) that were available before ES6. If you're interested in testing performance with newer JavaScript features, you might consider adding additional benchmark definitions.

**Other alternatives**

If you want to test alternative approaches or libraries for array reduction, here are a few ideas:

1. **Lodash**: Lodash is a popular utility library that provides a `mapObject()` function for merging objects.
2. **Array.prototype.reduceWith()**: Some browsers (like Chrome) provide an extension of the `reduce()` method called `reduceWith()`, which allows for more flexible reduction functions.
3. **Custom implementation**: You could also test custom implementations of array reduction, such as using a simple loop or recursion.

I hope this helps! Let me know if you have any further questions.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0

Browser/OS: Firefox 62 on Linux

View result in a separate tab

Test name	Executions per second
Using the spread operator	1304733.4 Ops/sec
Using Object.assign	957847.3 Ops/sec
Returning the reference	2485118.5 Ops/sec

Related benchmarks:

Array.reduce2 (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign vs Returning the reference

Created: 6 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Returning the reference

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):